It is known to cause a beam of electromagnetic radiation to impinge on and interact with a sample, then analyze the effect said interaction of said beam with said sample has on said beam, to arrive at sample characterizing data. At times a sample has distinguishable regions which are to be evaluated separately, and in that case it is necessary to know where upon said sample the electromagnetic beam is actually impinging. This can be accomplished by providing a means for allowing visual observation of a sample surface. A typical approach to this is to provide a beam which approaches the sample along a substantial normal thereto. This approach works to provide a view of the sample, but can not be applied to show where an beam of electromagnetic radiation directed toward said sample at an oblique angle of incidence impinges thereupon. To achieve that result a camera must be oriented along the path of the beam oblique angle of incidence. The reason for this is that the view of the sample is based upon interception of electromagnetic radiation scattered from the sample, and where a camera is positioned above a sample with a smooth surface, very little scattering theretoward occurs, whereas far more detectable electromagnetic radiation is available along the locus of the beam.
PCT (PCT/EP2008/087217 WO), and EPO (No., EP 947 445 A1), Patent Applications by Horiba Jobin Yvon are disclosed as they disclose using a beam splitter ahead of a data detector, which beam splitter directs sample illuminating electromagnetic radiation directed theretoward into a visualization device, while passing a sample investigation electromagnetic radiation beam into a data detector. A drawback of this approach is that some sample investigation electromagnetic radiation is diverted from the data detector, thereby reducing intensity of the sample investigating beam available to the data detector.
The present invention provides a convenient to use system and method for enabling such visual observation capability, that allows avoiding decreasing the intensity of the sample investigation beam arriving at a data detector while allowing the ability to provide illuminating electromagnetic radiation to a visualization device.